Vented Multi-Angled Pilot Fuel Nozzle Venturi for Heat Durability
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Solution Overview
Problem
The aft heat shield of fuel nozzle assemblies in TAPS combustors is vulnerable to high temperatures, leading to oxidation and reduced durability.
Innovation Solution
A vented venturi design with an air flow passage and oxidizer outlet ports within the venturi wall provides cooling air to the inner and outer surfaces, minimizing heat shield area and optimizing the venturi's shape to reduce wall gas temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat shield is provided at the outlet end of the venturi to protect the fuel nozzle assembly, then the protection against high temperatures is improved, but the heat shield area increases leading to greater exposure to oxidation and reduced durability
Solution Approach 1:
The invention extracts the heat shield from the system by using the venturi wall itself as the protective barrier through cooling air flow passages. Instead of adding a separate heat shield component, the cooling passages are integrated directly into the venturi wall to protect it from high temperature combustion gases, thereby eliminating the oxidation-prone heat shield while maintaining temperature protection.
Solution Approach 2:
Cooling air acts as an intermediary substance that flows through passages in the venturi wall to create a thermal barrier between the combustion gases and the venturi material. This cooling air mediates the heat transfer process, protecting the venturi surface from direct exposure to high temperatures without requiring an additional heat shield component.
2Temperature
If the venturi wall is thickened to withstand high temperatures, then the temperature resistance is improved, but the device complexity and weight increase
Solution Approach 1:
The invention uses pneumatic cooling by flowing compressed air through passages embedded in the venturi wall. This allows the venturi to withstand high temperatures without requiring excessive wall thickness, as the cooling air actively manages thermal loads through fluid dynamics rather than relying solely on thermal mass.
3Temperature
If cooling air flow passages are added to the venturi wall, then the temperature control is improved, but the device complexity increases
Solution Approach 1:
The venturi wall serves multiple functions: it maintains the aerodynamic flow path, provides structural support, and acts as a thermal management system through integrated cooling passages. This multi-functionality allows temperature control to be achieved without adding separate cooling components, thereby limiting the increase in device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The vented venturi design effectively reduces high temperatures on the venturi surface, enhancing the durability and longevity of the fuel nozzle assembly.
Implementation Method 1
an oxidizer flow passage within the annular wall, the oxidizer flow passage delivering cooling air to an inner surface and an outer end portion of the venturi
Data Source
AI summary
A pilot fuel nozzle assembly includes a fuel nozzle, a swirler, and a vented pilot venturi. The vented pilot venturi has an annular wall with an oxidizer flow passage therein and a venturi expansion surface. The venturi expansion surface includes a plurality of conical surface segments extending circumferentially about the fuel nozzle centerline axis. At least two conical surface segments are joined together mechanically. One or more of the plurality of conical surface segments have a plurality of venturi oxidizer outlet ports extending through the venturi expansion surface. The plurality of venturi oxidizer outlet ports are circumferentially spaced about the fuel nozzle centerline axis.